899 resultados para Investigative experimental work


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The process of knowledge construction is associated with physical or mechanical view of the phenomenon. In mechanical engineering courses should supplement their courses with physical or virtual learning devices to aid visualization of these phenomena. For the purpose of improving the mechanical engineering department laboratory practice was developed, through a project, a didactic device a trellis. The purpose of this work is the detailed study by comparing the theoretical results with the experimental results collected through the specific strains collected in the Catman. The study was iniatially done with nodes made of aluminum, giving results with high errors not allowing a good conclusion of results. For best results were achieved an improvement of the structure with strict we support the lattice and, thus, further study and greater quality of lattice structure

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Pós-graduação em Química - IQ

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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An excitation force that is not influenced by the system's states is said to be an ideal energy source. In real situations, a direct and feedback coupling between the excitation source and the system must always exist. This manifestation of the law of conversation of energy is known as Sommerfeld Effect. In the case of obtaining a mathematical model for such system, additional equations are usually necessary to describe the vibration sources and their coupling with the mechanical system. In this work, a cantilever beam and a non-ideal electric DC motor that is fixed to the beam free end is analyzed. The motor has an unbalanced mass that provides excitation to the system proportional to the current applied to the motor. During the motor's coast up operation, as the excitation frequency gets closer to the beam first natural frequency and if the drive power increases further, the DC motor speed remains constant until it suddenly jumps to a much higher value (simultaneously the vibration amplitude jumps to a much lower value) upon exceeding a critical input power. It was found that the Sommerfeld effect depends on some system parameters and the motor operational procedures. These parameters are explored to avoid the resonance capture in Sommerfeld effect. Numerical simulations and experimental tests are used to help insight this dynamic behavior.

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The characterization of the hyperbolic power-time (P-tlim) relationship using a two-parameter model implies that exercise tolerance above the asymptote (Critical Power; CP), i.e. within the severe intensity domain, is determined by the curvature (W') of the relationship. The purposes of this study were (1) to test whether the amount of work above CP (W>CP) remains constant for varied work rate experiments of high volatility change and (2) to ascertain whether W' determines exercise tolerance within the severe intensity domain. Following estimation of CP (208 ± 19 W) and W' (21.4 ± 4.2 kJ), 14 male participants (age: 26 ± 3; peak [Formula: see text]: 3708 ± 389 ml.min-1) performed two experimental trials where the work rate was initially set to exhaust 70% of W' in 3 ('THREE') or 10 minutes ('TEN') before being subsequently dropped to CP plus 10 W. W>CP for TEN (104 ± 22% W') and W' were not significantly different (P>0.05) but lower than W>CP for THREE (119 ± 17% W', P<0.05). For both THREE (r = 0.71, P<0.01) and TEN (r = 0.64, P<0.01), a significant bivariate correlation was found between W' and tlim. W>CP and tlim can be greater than predicted by the P-tlim relationship when a decrement in the work rate of high-volatility is applied. Exercise tolerance can be enhanced through a change in work rate within the severe intensity domain. W>CP is not constant.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In this work it is proposed the use of a chemical activity, in which a corrosion process occurs, aiming to provide to the student relationship among the learning concepts and corrosion phenomena that occur everyday. It is suggested that the experiment development is based on Vygotsky theory, so that students work in groups, which may facilitate social interaction among students and results discussion among groups under professor guidance. This proposal can provide the involved concepts learning, as well as student training such as a critical and reflexive individual.

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Pós-graduação em Engenharia Mecânica - FEIS

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Pós-graduação em Televisão Digital: Informação e Conhecimento - FAAC

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In this work the main concepts to apply to dynamic signal analysis technique for rotating machines known as order analysis, discussing their characteristics and applying it on an experimental test rig. It aims to characterize the dynamic behavior of experimental test rig in run up and run down tests, it's operational speed range and the identification of the critical speed of shaft rotation. The results of the critical speed and stationary natural frequency of the shaft are discussed

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The torsional stiffness of chassis is one of the most important properties of a vehicle's structure and therefore its measurement is important. For the first time, the torsional stiffness was considered on the design of a prototype Baja SAE of the team from UNESP - FEG, Equipe Piratas do Vale Bardahl. According to the team's opinion, the increase of stiffness on this prototype, called MB1114, made possible a great improvement in its performance during competitions. In this work, the experimental evaluation of the torsional stiffness from this prototype is performed, detailing the analysis of results, as well as, the hysteresis' effect, least-squares regression and uncertainty analysis. It also shows that it is possible to measure the torsional stiffness of chassis with a low experimental uncertainty without expending many resources. The test rig costed R$ 32,50 due the reuse of materials and the use of instrumentation already available on campus. Furthermore, it is simple to produce and can be easily stocked. Those features are important for Baja and Formula SAE teams. Lastly, the measured value is used to validate the finite element analysis performed by the team during this prototype's design, because similar studies will be performed for the new cars. After investigating the finite element analysis, one result 13,5% higher than the measured value was reached. This difference is believed to be occurred due the imperfections of the finite element model, in other words, for not been possible to simulate every phenomena present on the real model

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In this work the main concepts to apply to dynamic signal analysis technique for rotating machines known as order analysis, discussing their characteristics and applying it on an experimental test rig. It aims to characterize the dynamic behavior of experimental test rig in run up and run down tests, it's operational speed range and the identification of the critical speed of shaft rotation. The results of the critical speed and stationary natural frequency of the shaft are discussed